Yota Kawamura

Impact of vascular remodeling on the coronary plaque compositions: An investigation with in vivo tissue characterization using integrated backscatter-intravascular ultrasound

Recent studies have indicated that positive remodeling is strongly associated with development of acute coronary syndrome (ACS). The aim of this study was to compare plaque composition of vascular remodeling patterns by an established in vivo tissue characterization method using integrated backscatter (IB)-intravascular ultrasound (IVUS). The study population consisted of 41 consecutive patients who received IVUS prior to percutaneous coronary intervention. Remodeling index (RI) was calculated as the external elastic membrane (EEM) area at the minimal lumen area (MLA) site divided by average EEM area at the proximal and distal reference sites. The patients were divided into two groups based on RI: positive remodeling (PR) defined as RI>1 and non-PR as RI<or=1. A total of 21 areas centered at MLA per lesion site were evaluated by IB-IVUS at 1mm intervals. The occupancy rate of four tissue types within atherosclerotic plaques was compared between the two groups. Percent lipid volume in the PR group (n=20) was significantly greater than the non-PR group (n=21) (40.5+/-14.8% vs. 26.4+/-15.9%, p<0.001). In contrast, % fibrous volume in the PR group was significantly lower than the non-PR group (49.9+/-9.4% vs. 56.1+/-9.6%, p=0.042). Percent dense fibrous volume and % calcified volume were slightly but significantly lower in the PR group compared with the non-PR group (dense fibrous: 6.8+/-5.0% vs. 11.6+/-8.4%, p=0.034, calcified: 2.6+/-2.0% vs. 5.1+/-4.4%, p=0.026). In conclusions, PR lesions contain more lipid-rich and less hard plaque components compared with non-PR lesions, which may account for the higher incidence of ACS and plaque vulnerability.

A familial case of multiple recurrent cardiac myxomas

The familial variant of cardiac myxomas is an autosomally dominant disease. Here, we report a case of recurrent multiple cardiac myxomas wherein the patient, a 36-year-old woman who was referred for palpitations and nocturnal dyspnea, had a relevant familial history. Her mother had undergone extirpation of cardiac myxoma when she was about 50 years old. Echocardiography showed the presence of multiple cardiac myxomas. One of the cardiac myxomas nearly obstructed the left ventricular inflow; therefore, we extirpated the myxomas under cardiopulmonary bypass and cardioplegic arrest. The operation was uneventful and the postoperative clinical course was good. Pathological examination confirmed that the extirpated mass was a myxoma. Approximately 3 years after the first cardiac operation, we found a recurrent cardiac myxoma in the same patient. She then underwent a second operation and was discharged without any complications. Pathological examination also confirmed that the cardiac mass was a myxoma and that there was no malignancy. <Learning objective: This familial multiple cardiac case is a rare case because of its multiplicity, location (especially, the myxoma in right atrium is rare) and recurrence at the same position. And we may suggest the pitfall or prevention for recurrence of cardiac myxoma.>.

A case of takotsubo cardiomyopathy leading to the diagnosis of myasthenia gravis

A 52-year-old woman presenting with shortness of breath and having no related past medical history was diagnosed with takotsubo cardiomyopathy. However, she revealed respiratory failure atypical with takotsubo cardiomyopathy. We diagnosed myasthenia gravis with myasthenic crisis by acetylcholine receptor-binding antibody titer with mediastinal tumor. Physical or emotional stress is well known to trigger the onset of takotsubo cardiomyopathy. Similarly, myasthenia crisis is also triggered by stress. Here, we report a case of simultaneous occurrence of takotsubo cardiomyopathy and myasthenia crisis.